<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>俄罗斯方块</title>
    <style>
        #root{
            width: 500px;
            height: 500px;
            background: #000;
            margin: 0 auto;
            position: relative;
        }
    </style>
</head>
<body>
    <div id="root">

    </div>
    <div style="text-align:center">
        <button id="btnDown">向下移动</button>
        <button id="btnRemove">移除</button>
        <button id="btnAdd">添加显示者</button>
    </div>
</body>
</html>
